Transmission of intelligence



E. H. COLPITTS AND H DE F. ARNOLD.

TRANSMISSION OF INTELLIGENCE. v APPLICATION FILED SEPT 3, I915. RENEWEDIAN. I3, I92I.

Patented Aug. 23, 1921. *Wwv- MW Q I s: Q q

/n I/enfons:

' tions in message wavds-of 'comparativelylow' quired high frequency,but of a power value I UNITED STATES. PATENT "oFFrc-E.

EDWIN n. coLrrr'rs, or nasal omen, Am) HAROLD DE ronns'r ARNOLD, orMaren- WOOD, NEW JERSEY ASSIGNORS, BY MESNE ASSIGNMENTS, TO WESTERNELEC- TRIO COMPANY, INC0E1ORA-TED,- A. CORPORATION OF NEW YORK.

TBANSMIsSION OF INTELLIGENCE.

Specification of Letters Patent.

Patented All. 23, 1921..

Application filed September 3, 1915, Serial No. 16,78 9. Renewed January13, 1921. Serial No. 437,125.

To allwitomc't may concern: 7 v 7 Be it known that we, EDWIN H. CoLrrrrsand Harrow Dn Fonnsr ARNOLD, citizens of the United States, residingrespectively at East Orange, in the county of Essex and State of NewJersey, and Maplewood, in the county of Essex and State of New Jersey,have invented certain new and useful Improvements in the Transmission ofIntelligence, of which the following is a full, clear,

concise, and exact description.

This invention relatesto the transmission of intellligence, and moreparticularlyto systems in which sustained oscillations'of high frequencyare employed as carrier waves, and in which the amplitude of suchoscillations is made to vary .in accordance with variafrequency.

Its object is the production of high frequency waves which are areaccurately modulated in accordance with the messagewave and ofsufficient power for effective long distance communication.

To these ends the invention provides for the generation of carrier wavesof the recomparable with that of the message impulses, as distinguishedfrom that ultimately required for effective transmission. It furtherprovides for modulating or changing the amplitude of these oscillationsof low power in accordance with the form of the message wave and foramplifying the power value of the modulated high frequency oscillationsto -a degree suificient for long range communication.

The arrangement of this invention makes it possible to use, as the lowfre uency message source, a telephone transmitter or other devicecapable of handling only a small amount of energy, whereas in previoussysterns it has been assumed that for effective long range'communicationit was essential that the low frequency-message source should be onecapable of handling an amount of power comparable with that necessaryfor radiation.

In other words, the power value of the generated oscillations is chosenwith reference' to the power delivered by the primary modulating sourcerather than with reference to the amount of power necessary for radiation. I Y

, The invention will be more clearly understood byv reference to theaccompanying drawing, in which Figure 1 represents the system of thisinvention arranged for radio telephonic transmission; andFig, 2 shows animprovement on the system of Fig. 1, in-

which are the inventions'of others and which have been made the subjectmatter of other plifier 3 includes the anode 5, condenser 10,

primary winding 11 of transformer 12, Wind ing 13 of transformer 14,condenser 15, bats 'corp'orating certain specific modificationsamplifier includes the cathode l, the electrode 1 Y K tery 16and thecathode 4. An impedance coil 17 is inserted, as shown, to provide a.

direct current path for space current supplied to the amplifier 3 by thebattery 16.

Secondary winding 18 of transformer 14.

is bridged across the cathode 4 and electrode 6, as shown, and serves tofeed back, into the input circuit of the amplifier, currents generatedinthe output circuit, thereby causing the amplifier 3 to function as agenerator of high frequency oscillations, the periodicity of which isdetermined by the adjustment of condensers 10 and 15. For a morecomplete understanding of this action, reference may be had to theColpitts Patent 1,137,384:.

Primary winding 19 of transformer 8 is connected through anothertransformer 20 to a source of low frequency impulses, which in thiscasecomprises a telephone transmitter 21 and a battery 22. By thisarrangement the telephonic electromotive forces, generated bytransmitter 21. in the winding 7, serve to vary the amplitude of thehigh frequency oscillations produced by the amplifier 8, and cause to beimpressed on the transformer 12 a wave impressed.

I amplifiers 27, 28 and 29.

25 be made to produce either fication or a current amplification, arediscussed in the Arnold Patent No. 1,129,942

35 which forms with it 65 frequency action of the system. The resistance25, in

, parallel withthe condenser 24 andthe wind-- ing 23, is included in theinput circuit of an amplifier 26, also ofthe thermion-ic type.

Amplifier26 serves in the Well known manner to amplify the power valueof the modulated high frequency oscillations produced by theamplifier'3. In'this case, this power.

amplification isdirected mainly to increasing the oltage of themodulated high frequency to the degree necessary -for controlling theinput circuits of the high current The features of,design, whereby athermionic amplifier of the type in question may a voltage ampliof March2, 1915, and the 1,329,283 of January 27, 1920.

The'output circuit of" amplifier 26 includes Arnold Patent theinductance 30 for providing a direct current path for the space currentdelivered to-the amplifier 26 by battery 31. In multiple with theinductance 30 is a condenser 32 an anti-resonant circuit tuned to thefrequency of the high frequency oscillations, and consequently of highim; pedance thereto.

Theinput circuits of the current amplifiers 27, 28 and 29 are bridged inmultiple across the terminals of condenser 32. This and also other armments for producing the same result are isclosed in the Arnold Patents,1,129,942 and 1,129,943 of March 2, 1915. In the present case, thecathodes,

33, 34-and 35 are connected in series with a battery 36 and an Thecommon output circuit of the ampli-.

fiers 27, 28 ,and 29 includes winding 38 of, the output transformer 39'and -a. sourceof direct current, which, in this case, is shown, as adirect current generator 40, though it is obvious that any 'othersourceof direct current may be employed. A condenser 41 is preferablyshunted'about the terminals of the generator 40 in order to furnish alow impedance path for the l1igh-frequency.cur-

rents. The secondary winding42 of the transformer 39 is connected inseries with the antenna 43, and serves to'impress thereon high currentsof large power value This resistance serves as a from an antenna but ofa adjustable resistance 37 and are heated to the required degree ofincandescence by current supplied from this 50 battery. this case theoutput amplifiers 26 is coupled by the winding 57 .to the resonantcircuit made'up of the windmodulated in accordance with the telephonicwave generated by transmitter. 21.

The'amplifiers 27, 28 and 29 are preferably of thehigh' current typedescribed in the Arnold Patent No. 1,129,942 and in Arnoldsapplication-,gSer-ial No. 277,578, filed February 17,1919, and while,for the sake of illustration, only three of these amplifiersarehereinlshown, it has been .found in practice thatany number of suchamplifiers may beconnected in multiple, depending upon the amount ofpower required, an

that two or three hundred of such amplifiers connected in multipleproduce a power amplification suflicient for effective long rangecommunication.

frequency oscillations is employed. In this case, the high frequencyoscillations are generated 'in a separate thermionic amplifier '50,whose operation will befound described in patent to Hartley 1,356,763,patented October 26, 1920, and which is designed to generate sustainedoscillations of a frequency sufiiciently high 5 for radiation powervalue comparable with that developed by the transmitter 21. These highfrequency .oscillations, together with the oscillations -of telephonicfrequency, are impressed .upon the input circuit of an amplifier 51andscrveto produce in the out ut-circuit of this amplifier a modulated"gh frequency wave similar to that developed by the. amplifier 3, asdescribedand cla'med in the patent to Van der Bijl 1,350,752, patentedAugust 24, 1920.

These modulated high frequency oscillations are subjected to a voltageamplification bvmeans of a plurality of amplifiers of the type of'26,whose 5.6 offaboutl microfarad capacity each. In circuit of the voltageboth the amplifier 'ing 58 and condenser 59. .Condenser 59 is shunted bya high resistance 60 and is included in the inputcircuit of the poweramplifiers 27, 28, etc.'

It has been found feasible to heat the filaments-33, '34, etc, from analternating current source, and, as shown in Fig. 2, the filaments 33,34, etc, are heated from a 60 cycle generator 61." Where an alternatingcurrent source is employed for this purpose,

the filament circuit should be shunted b an inductance 62,'the-m-iddlepoint 63 of w ioh by condensers 55 and In the development of the systemof Fig.

is connected to the output. circuit through a "ill resistance-64. .Eachhalf of the inductance '62 is shunted by a condenser 65.

in a practical employment of the system herein described in whicheffective long range communication has been obtained, six voltageamplifiers of the type of 26 were employed, and were supplied with spacecurrent from a gener tor 5a of 500 volts output. 1 250 of the amplifiersof the type of 27 and 28 were employed, and were supplied with spacecurrent from a direct current generator 66 shunted by a condenser 67 of100 microfa-rads capacity and deli ering space current at a; voltage of600. The filament circuit was supplied by a60 cycle generator 61delivering current at a voltage of 10 volts. The inductance 62 wasgivena value of .4 milli-henry and the condensers 65 each had a capacityoflOO microfarads.

Although this invention has been described in connection with radiosignaling, it is also applicable to'selective transmission of any kindand to high frequency transmission over conducting circuits as well asto radio transmission;

What is claimed is: 1

' l. The'method of signaling which consists in modulating carrier wavesof insufficient power for transmission to agdistant station and inincreasing the power of said modulated waves before they aretransmitted.

2. The method which consists in modulating, in accordance with otherwaves,

lll

carrier waves of "insufficient power for transmissionto a distantstation and in in-; creasing the power of sand modulated waves beforethey are transmitted, V

' 3. The method which consists in modulating, in accordance withelectric current waves, carrier waves of insufficient power fortransmission to a distant station and in increasing the power of saidmodulated waves before they are transmitted.

4. The method which consists in modulating, in accordance with signalcurrents,

=carrier waves of insufficient power for transmission to a distantstation and in increas ing the power of said modulated waves before theyare transmitted.

5. The methodiof signaling which conslsts in generating carrierv waves,supplying message impulses of a power value comparable to that of saidwaves, modulating said waves in accordance with saidiim ulses and inamplifying the power value '0 the modulated waves to a degree sufficientfor long distance transmission;

6I In a signaling system, the combination of means for-supplyingmodulated carrier waves, a conductor ada ted to transmit said waves, andan amp 'fier between said means and said conductor whereby said wavesareamplified beforethey are sent to a distance.

7. In a signaling system, the combination of means for supplying.modulated carrier waves, a conductor adapted to transmit said waves, anda vacuum tube of the audion type between said means and said con-oductor whereby said waves are amplified before theyare. sent to adistance.

9'. The method of controlling'the emis-' sion of high power, highfrequency waves bv means of feeble signal waves which consists ingenerating feeble high frequency oscillations, modulating saidoscillations in their feeble state by means of said feeble signals, andamplifying said feeble modulated oscillations to the high power state inwhich they are to be transmitted.

10. The method of controlling the emis-' sion of high power, highfrequency waves by means of feeble signal waves which consists ingenerating feeble high frequency oscillay tions, modulatlng saldoscillations .in their feeble state by means of said feeble signals, andseparately amplifying the voltage and amperageofsaid feeble modulatedoscillations. p

11. The method ofcontrolling the emission 'ofhigh power, high frequencywaves by means of feeble signal waves which con sists in generatingfeeble high frequency oscillations, modulating said oscillations intheir feeble state by, means of said feeble signals, amplifying thevoltage, and sub sequently amplifying the amperage ofthe modulatedoscillations.

12. The method of controlling the emission of high power, high frequencywaves by means of feeble signal waves which consists in generatingfeeble high frequency oscillations, modulating saidoscillations in theirfeeble state by means of said feeble signals, amplifying saidfeeble-modulated osclllations into modulated oscillations having arelatively high voltage, and in amplifying said high voltage modulatedoscillations intomodulated oscillations having both a relatively highvoltage and a relatively high amperage.

13. The method of controlling the e1nission of high power, highfrequency waves by means'of,feeble signalwaves which consists [ingenerating feeble high-frequency oscillations, modulating saidoscillations in their feeble state. by meansof said feeble s gnals, andcaus ng'said modulated osc1lla tions to vary the potential across theinput circuit of asystem of thermionic amplifiers having a-lar'ge poweroutput.

14. The method "of "radio, transmission which-comprises modulating acarrier wave distant station,

" comprises modulating a carrier wave in ac= eordance with speech waves,

increasing the power of said modulated carrier w'ave beforetransmission, and radiating said wave of increased power.

means for supplying carrier Waves ofin sufiicient power for transmissionto a dis-' tant' station, I means for modulating said waves, and meansfor increasing the power of said modulated Waves before transmission. 1I

'17, A signal system comprising a source of carrier waves, means formodulating said u Waves in accordance with signals, a carrier cuit ofsaid repeater, ulated oscillations to vary the, potential across theinput circuit of a system of'ther wave transmission conductor, and means7 connecting said modulating means and said conductor for inereaslng thepower of said modulated waves.

18. The method of transmitting signals through space which consists ingenerating oscillations of radio frequency having a power valuecomparable with that of the signal impulses to be transmitted, impressmgsaid oscillations together with said impulses on the input circuit of, athermionic repeater, whereby modulated high frequency oscillations areproduced in the output cirand causing said mod? mionie amplifiers havinga large power output: a 1 a I '19: In a signaling system, thecombination of means for rents,a conductor adapted to transmit saidwaves, and an amplifier between said means' and said conductor wherebysaid waves are amplified" before they are sent to 'a dis:.

tance. i

tion otmeans for supplying carrier waves modulated by other waves, aconductor adapted to transmit said Waves, and an. am-' pllfierbetweensaid means and sa1dconduc.-'

tor whereby said Waves are amplified before they are s'ent to adistance.

' 21. The combination with means for; gencrating high frequencyoscillations and for modulating .sa'id oseillationsin accordancearranged in multiple, fier energized bysaid with low frequency mitted,of a plurality of current amplifiers and-a voltage impliinto said.current amplifiers,

creased;

power 'for transmission to a transmission system comprlsing circuit, a t

"the high power :state supplying carrier waves ;m'odulated'1n accordancew1th signal curimpulses to be trans:

means and working whereby the Power of a d modulatedoscillations s 1n--'erating high bfreqlienc oscillations and for modulating sa'id oscilations in accordance with" low equency impulses to be "transmitted, of aplurality of thermionic amplifiers'arranged in multiple having a com moninputcircuit, and a thermionic amplifier adapted to be energized by saidmeans and working into said input circuit, whereby the power of saidmodulated oscillations is increased. i

23. The combination with means for generating high frequencyoscillationsand for modulating saidoscillations in accordance with ,lowfrequency impulses to be transmitted, of a plurality of thermioniccurrentamplifiers arranged in multiple havinga common in ,ut circuit anda common output ermionic voltage-amplifier associated with said. meansand working into said input 'circuit, whereby the power of saidmodulated oscillations is increased and an antenna circuit coupled withsaid output circuit.

24, Thecombination with a thermionic amplifier having an input circuitand an ,output circuit, of means for impressing a frequencyelectromotive force, and means connected with said output circuit foramplifying said high frequency oscillations to in which they are to betransmitted.

25. In aisystem for radio, transmission, the combination with athermionic amplifier having an input circuit and an output circuit, ofmeans for impressing an audio frequency electromotive force and aradio'frequency electromotive force of comparable I f; and feebieintensities on said input circuit 20.In a' signaling system, the combinng whereby a low power modulated high frequency current is produced insaid output circuit, and means'for' amplifying said modul'ated currentto a high it isto be transmitted.-

26.,In a s the combination with a thermionic repeater having andnputcircuit and an output circuit, of means for'iinpressing an audiofrequency electromotive force and a radio frequency electromotive forceofcomparable magnitudes on said inputcircuit whereby a modulated highfrequency current is produced in said output circuit, and a plurality ofthermionid repeaters coupled with said output circuit for amplifyingsaid modulatedfhi h frequencycurrents to a high power Va ue.

power state in which 27. The method 0f carrier current. telephony whichincludes generating speech waves and carrier current Waves of comparablemagnitude, impressing all of said waves upon a modulator, amplifying themodu lated carrier waves and transmitting them to a distant station,said carrier waves be-' fore amplification being too feeble fortransmission and reception at said station. a 28. The method of higlfrequency transmission which includes generating low frequenc ymodulatlng waves and carrier current waves of comparable magnitude, im-

pressing all of said waves upon a modulator, amplifying the modulatedcarrier waves 15v and transmitting them to a distant station,

said carrier waves before amplification be- .ing too feeble fortransmission andreception at sald station.

In witness whereof, We hereunto subscribe 20

